ASP.Net MVC and using Linq to Entities - asp.net-mvc

Question

I'm following an MVC 5 tutorial: http://www.c-sharpcorner.com/article/dashboard-application-with-asp-net-mvc-5-and-jquery/
but the Author left out 1 of the features - the middle panel - "Orders" (which is the orders for all customers). It has a View Details link but no code and partial view is displayed when clicked.
So I'm trying to do create that partial view but having trouble with writing the Linq To Entities.
I am trying for just a partial view that is like a header/multi detail:
CustomerName CustomerImage
OrderDate
Quantity ProductType, ProductName, ProductImage
OrderDate
Quantity ProductType, ProductName, ProductImage
CustomerName CustomerImage
OrderDate
Quantity ProductType, ProductName, ProductImage
Here is the ViewModels I created to represent the above:
public class OrderDetailsViewModel
{
public int Quantity { get; set; }
public string ProductType { get; set; }
public string ProductName { get; set; }
public string ProductImage { get; set; }
}
public class CustomerOrdersViewModel
{
public string CustomerName { get; set; }
public string CustomerImage { get; set; }
public DateTime OrderDate { get; set; }
public ICollection<OrderDetailsViewModel> OrderDetailsViewModel{ get;
set; }
}
Here is the DbContext and the models that the Author created:
DbContext:
public class DashboardContext : DbContext
{
// Constructor - inherits the base constructor.
public DashboardContext() : base("DashboardOrder")
{
}
public IDbSet<Customer> CustomerSet { get; set; }
public IDbSet<Order> OrderSet { get; set; }
public IDbSet<Product> ProductSet { get; set; }
public IDbSet<OrderDetails> OrderDetailSet { get; set; }
}
Customer:
public class Customer : IEntity
{
public Customer()
{
Orders = new List<Order>();
}
public int ID { get; set; }
public string CustomerName { get; set; }
public string CustomerEmail { get; set; }
public string CustomerPhone { get; set; }
public string CustomerCountry { get; set; }
public string CustomerImage { get; set; }
public virtual ICollection<Order> Orders { get; set; }
}
IEntity:
public interface IEntity
{
int ID { get; set; }
}
Order:
public class Order : IEntity
{
public Order()
{
OrderDetail = new List<OrderDetails>();
}
public int ID { get; set; }
public DateTime OrderDate { get; set; }
public virtual Customer Customer { get; set; }
public virtual ICollection<OrderDetails> OrderDetail { get; set; }
}
OrderDetails:
public class OrderDetails : IEntity
{
public int ID { get; set; }
public int Quatity { get; set; }
public virtual Order Order { get; set; }
public virtual Product Product { get; set; }
}
Product:
public class Product : IEntity
{
public Product()
{
OrderDetails = new List<OrderDetails>();
}
// Auto-implemented properties.
public int ID { get; set; }
public string ProductName { get; set; }
public decimal UnitPrice { get; set; }
public int UnitsInStock { get; set; }
public string ProductImage { get; set; }
public string ProductType { get; set; }
public virtual ICollection<OrderDetails> OrderDetails { get; set; }
}
Here is the Action Method in the DashboardController I was attempting to write.
I believe I want to read the Order Model which in turn has reference to the Customer and a list of Orders which in turn has a reference to the list of OrderDetail which has reference to the Product.
But I'm having a hard time with the "Linq to SQL" to get the data in the lists in the models to create my ViewModel to flatten it out and pass to my partial view as a list.
public ActionResult GetCustomerOrdersDetails()
{
List<CustomerOrdersViewModel> customerOrders = null;
using (DashboardContext _context = new DashboardContext())
{
// Using LINQ TO SQL and deferred execution via the "ToList".
customerOrders = (from o in _context.OrderSet
select new CustomerOrdersViewModel
{
CustomerName = o.Customer.CustomerName,
CustomerImage = o.Customer.CustomerImage,
OrderDate = o.OrderDate,
-- Here I need to process the list of Orders which in turn has a reference to the list of OrderDetail which has
reference to the Product.
ProductType = ?,
ProductName = ?,
ProductImage = ?,
Quantity = ?,
}).ToList();
}
return PartialView("~/Views/Dashboard/GetCustomerOrdersDetails.cshtml", customerOrders);
}

Answer 1

You first need a .GroupBy() clause to group the records by CustomerName, CustomerImage and OrderDate. Then because OrderDetail is a collection proeprty, you need a .SelectMany() to 'flatten that collection before projecting the result to your OrderDetailsViewModel model.
List<CustomerOrdersViewModel> model = db.OrderSet
.GroupBy(x => new { Name = x.Customer.CustomerName, Image = x.Customer.CustomerImage, Date = x.Date })
.Select(x => new CustomerOrdersViewModel
{
CustomerName = x.Key.Name,
CustomerImage = x.Key.Image,
OrderDate = x.Key.Date,
OrderDetailsViewModel = x.SelectMany(y => y.OrderDetail).Select(y => new OrderDetailsViewModel
{
ProductName = y.Product.ProductName,
Quantity = y.Quantity,
ProductType = y.Product.ProductType,
ProductImage = y.Product.ProductImage
}).ToList()
}).ToList();
return PartialView(model);
Then in the view you can use nested loops to display the details of each order
#model IEnumerable<CustomerOrdersViewModel>
....
#foreach(var order in Model)
{
.... // display details of customer name, date etc
#order.CustomerName
foreach(var item in order.OrderDetailsViewModel)
{
.... // display details of product, quantity etc for each order
#item.ProductName